- U-BT Cluj-Napoca (Basketball)
- U.C.D. (Football)
- UAB (American Football)
- UAB (Basketball)
- UAlbany (American Football)
- UC Capitals (Basketball)
- UC Davis (American Football)
- UC Irvine (Basketball)
- UC San Diego (Basketball)
- UCF (Basketball)
- UCF (American Football)
- UCLA (American Football)
- UCLA (Basketball)
- UConn (American Football)
- UD Leiria (Football)
- UD Oliveirense (Football)
- Udinese (Football)
- UE Engordany (Football)
- UE Santa Coloma (Football)
- Uganda (Netball)
- Uganda (Football)
- Uganda (Cricket)
- Uganda Under-19s (Cricket)
- Uganda Women (Cricket)
- Uganda Women (Lacrosse)
- UIW (American Football)
- Ukashir Farooq (Boxing)
- Ukraine (Football)
- Ukraine (Tennis)
- Ukraine (Volleyball)
- Ukraine (Basketball)
- Ukraine U19 (Football)
- Ukraine U21 (Football)
- Ukraine Women (Football)
- UL Lafayette (Basketball)
- ULM (American Football)
- Ulsan HD (Football)
- Ulster Rugby (Rugby Union)
- Umar Salamov (Boxing)
- UMass (Basketball)
- UMass (American Football)
- Umeå FC (Football)
- UMF Stjarnan (Football)
- UMMC KR (Cricket)
- Umraniyespor (Football)
- UNA Strassen (Football)
- UNC Asheville (Basketball)
- Union Omaha (Football)
- Union Saint-Gilloise (Football)
- Union Titus Pétange (Football)
- Unionistas (Football)
- United Arab Emirates (Football)
- United Arab Emirates (Cricket)
- United Arab Emirates (Rugby Union)
- United Arab Emirates A (Cricket)
- United Arab Emirates Falcons (Cricket)
- United Arab Emirates Under-19s (Cricket)
- United Arab Emirates Women (Cricket)
- United Arab Emirates Women Under-19s (Cricket)
- United Arab Emirates XI (Cricket)
- United Kingdom (Rugby Union)
- United Services Recreation Club (Cricket)
- United Services Recreation Club Lantau Women (Cricket)
- United States (Baseball)
- United States of America (Cricket)
- United States of America Under-19s (Cricket)
- United States of America Women (Cricket)
- United States of America Women Under-19s (Cricket)
- United States Women (Lacrosse)
- United States Women (Hockey)
- Universitario de Deportes (Football)
- Universitario de Ferrol (Basketball)
- University of North Dakota (American Football)
- University Sport South Africa (Cricket)
- UNLV (American Football)
- UNLV (Basketball)
- UP Nawabs (Cricket)
- UP Warriorz Women (Cricket)
- Urartu (Football)
- Urawa Reds (Football)
- Urbanrisers Hyderabad (Cricket)
- Uriel Lopez (Boxing)
- Uruguay (Football)
- Uruguay (Tennis)
- Uruguay (Rugby Union)
- Uruguay (Handball)
- Uruguay U20 (Football)
- US Dax (Rugby Union)
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- USA (Football)
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- USA (Basketball)
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- USA (Rugby League)
- USA (Volleyball)
- USA (Netball)
- USA (Handball)
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- USA Women (Basketball)
- USA Women (Volleyball)
- USC (American Football)
- USC (Basketball)
- USL Dunkerque (Football)
- USON Nevers (Rugby Union)
- UT Arlington (Basketball)
- UT Martin (American Football)
- UT Martin (Basketball)
- Utah (American Football)
- Utah (Basketball)
- Utah Hockey Club (Ice Hockey)
- Utah Jazz (Basketball)
- Utah Royals (Football)
- Utah State (American Football)
- Utah State (Basketball)
- Utah Tech (American Football)
- Utah Valley (Basketball)
- Utah Warriors (Rugby Union)
- UTEP (American Football)
- UTSA (American Football)
- Utsiktens BK (Football)
- Uttar Pradesh (Cricket)
- Uttar Pradesh Club XI (Cricket)
- Uttar Pradesh Women (Cricket)
- Uttarakhand (Cricket)
- Uttarakhand Women (Cricket)
- Uttarandhra Lions (Cricket)
- UWI Vice Chancellor's XI (Cricket)
- Uzbekistan (Tennis)
- Uzbekistan (Football)